Isomerization of α-pinene oxide to campholenic aldehyde over Lewis acids supported on silica and titania nanoparticles

Lewis acids supported on titania have been found more actives than analogous supported silica catalysts due to the higher surface area of the TiO2 support. The selectivity instead was found to be independent on the support used. Among the investigated samples, Zn-doped catalysts resulted the most selective. On the basis of FT-IR of adsorbed pyridine, the selectivity to campholenic aldehyde on these catalysts has been correlated to the strength of the Lewis acid sites. Optimising the preparation of the catalysts and reaction conditions, a maximum yield to campholenic aldehyde of 74% was obtained.